Winter Moth Update 2012

Early winter moth feeding that occurred prior to budbreak is evident in newly emerging tree leaves. Note the large size of the caterpillar at the top of the left leaf.

The up and down temperatures this spring affected winter moth development and feeding.  Abnormally warm temperatures early in the season brought on premature winter moth egg hatch. Many of the trees that the insect feeds on had yet to have buds swollen enough to allow entry into them for feeding. This was followed by colder temperatures that slowed budbreak of trees. It has been estimated by personnel at UMass that the wide variations of temperatures resulted in some death of winter moth larvae. Populations, however, seem to be high enough this year that there will still be much feeding damage.

Winter moth larvae that were able to find swollen buds to enter and feed on have had a longer period of time to feed in the bud due to the delay in budbreak.  Winter moth larvae are larger this year relative to plant development because of the early hatch.  This is resulting in much damage occuring prior to budbreak.  Control measures can not effectively be applied until after initiation of budbreak.  Many properties still have some trees that have yet to break bud. If you are a Cedarlawn Tree client and have 2 treatments scheduled we are applying first sprays as soon as possible to counteract this early feeding.  Your second treatment will be applied shortly after the first (within a week or 2) when all your trees have broken bud in order to provide the best protection and limit feeding damage.